While configuring one port for both data and voice Vlan,why should the port be in access mode only and not in trunk mode?Will i get the answer if i refer any CCENT video?
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Unsolved CCNA-Configure VLANs Part 2
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@anupam-pandey said in CCNA-Configure VLANs Part 2:
While configuring one port for both data and voice Vlan,why should the port be in access mode only and not in trunk mode?Will i get the answer if i refer any CCENT video?
On a Cisco switchport, when you receive tagged traffic. you would normally configure this as a trunk to help distinguish between vlans. Cisco IP Phones on cisco switchports work differently, CDP is used to identify the Cisco IP Phone. A cisco switchport for Cisco IP Phones are configured as access ports for untagged traffic from the data pc and the voice data is tagged.
Essentially, you're creating a trunk logically without configuring it. An IP Phone tags with the correct Voice VLAN that the switch can read and place into correct voice vlan. Data packets sent through the IP Phone to the switch untagged. The switch places the untagged traffic into the configured data vlan on the switchport.
I'm not sure if I went into that explanation or not without reviewing the episode.
Cordially,
Ronnie Wong
Edutainer Manager, ACI Learning [ITPRO]
*if the post has answered the question, mark as solved.
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To expand upon Ronnie's answer, you can technically do either.
For non-Cisco phones on non-Cisco switches, if there is no option of Voice VLAN on the switch, the switchports would be configured as trunks (or 'general' ports), with the data VLAN set as native/PVID and then have the voice VLAN tagged/trunked to the phone. In the end, that is what the phone cares about, assuming it is split on to a different VLAN than the data traffic. So if data is on VLAN 1 and voice is on VLAN2, the port would be configured U1/T2.
The Voice VLAN function makes this a bit easier and essentially automates the process. Not only does it provide the same VLAN trunking functionality as above, but it also uses CDP/LLDP to tell the phone what VLAN it should be on. Without this, each phone would need to be manually configured for VLANs (which can by quite time consuming if you aren't otherwise provisioning them). It also simplifies the switch config since you don't need to worry about configuring every port as a trunk and excluding all the other VLANs off.
But to answer your question, in Voice VLAN mode, it isn't purely an access port, nor purely a trunk port. It's a special mode that functions a bit like a hybrid with added benefits. Hope that helps.
